How to Fix ISDone.dll and Unarc.dll Error Code -6 (Exclusive)
If you’re a gamer or frequently install large software packages, you’ve likely encountered the dreaded "ISDone.dll" or "Unarc.dll" error. Specifically, Error Code -6—often accompanied by the message "file read operation failed" or "the archive data is corrupted (decompression fails)"—is a common headache.
This error is almost always related to the decompression process. Here is a definitive guide to understanding why this happens and how to fix it for good. What Does Error Code -6 Mean?
Error Code -6 is an "Exclusive" error, meaning the installer cannot access or decompress the necessary files. This is usually caused by one of three things:
RAM Instability: Your system memory is failing to handle the data stream.
Antivirus Interference: Security software is locking the file while the installer tries to write to it.
Corrupt Source Files: The installer itself (often a highly compressed "repack") was downloaded with missing or broken data. Step 1: Disable Real-Time Protection isdonedll unarcdll error code 6 exclusive
This is the most frequent culprit. Antivirus software, including Windows Defender, often flags the decompression of large chunks of data as suspicious behavior and "locks" the files. Open Windows Security > Virus & threat protection. Select Manage settings. Toggle Real-time protection to Off.
Important: Also disable any third-party software like Avast, Malwarebytes, or Bitdefender during the installation. Step 2: Increase Virtual Memory (Paging File)
Large installers require significant memory. If your physical RAM is full, Windows uses your hard drive as "Virtual Memory." If this isn't configured correctly, the decompression crashes with Error -6.
Type "Performance" in the Windows search bar and select Adjust the appearance and performance of Windows.
Go to the Advanced tab and click Change under the Virtual Memory section.
Uncheck "Automatically manage paging file size for all drives." How to Fix ISDone
Select your C: drive, click Custom size, and set both Initial and Maximum size to at least 8000 MB (or 1.5x your physical RAM). Click Set, then OK, and restart your PC. Step 3: Run the Installer in Safe Mode
If background services or drivers are causing "exclusive" access issues, Safe Mode is the cleanest environment for an installation. Press Win + R, type msconfig, and hit Enter. Go to the Boot tab and check Safe boot. Restart your PC.
Run the game installer. If it works, return to msconfig to uncheck Safe boot and restart normally. Step 4: Check for RAM Issues (The Hardware Fix)
If you see Error -6 across multiple different installers, your RAM might be the problem. Search for Windows Memory Diagnostic and run it. Your PC will restart and check for hardware errors.
If it finds errors, you may need to reseat your RAM sticks or replace a faulty module. Step 5: Verify the Download (The "Corrupt" Fix)
If you downloaded the game via a Torrent or a multi-part download, one single bit of corrupted data will trigger Unarc.dll Error -6. What Does "Exclusive" Mean in "Error Code 6 Exclusive"
Force Recheck: If using a torrent client, right-click the download and select "Force Recheck" to ensure every piece of data is 100% intact.
Clear Temp Folder: Press Win + R, type %temp%, and delete everything in that folder before trying the install again. Summary Table Antivirus Lock Disable Windows Defender and Real-time protection. Out of Memory Increase Virtual Memory (Paging File) to 8GB+. Permissions Right-click the Installer and "Run as Administrator." Corrupt Files Re-verify download or re-download the installer.
Pro Tip: Always ensure you have at least double the required installation space free on your drive. Highly compressed archives need massive amounts of "scratch space" to decompress successfully.
Here’s a helpful, easy-to-follow story about the “ISDone.dll” and “Unarc.dll” error code 6 error, and how one person fixed it.
In computing, "exclusive" often refers to file locking or memory access modes. When the error says "exclusive," it implies that the installer attempted to write or read a file with exclusive rights (preventing other processes from touching it), but the operation failed. This can happen due to:
Follow these methods in order. Method 1 solves 80% of cases.
Error code 6 can trigger when Windows runs out of exclusive contiguous memory space.
Win + R, type sysdm.cpl, go to Advanced > Performance > Settings.